Capacitor

ABSTRACT

In order to ensure that a braising material applied onto the surface of a header pipe does not enter communicating passages for coolant intake/outlet at a connecting block during the furnace braising process implemented to weld the connecting block utilized to connect a liquid tank to the header pipe, pipe-like projections are formed at the pair of communicating passages for coolant intake/outlet formed at the connecting block for liquid tank connection on the side where the header pipe is connected and the pipe-like projections inserted at holes of the header pipe clad with a braising material are welded to a condenser to constitute an integrated part thereof.

TECHNICAL FIELD

The present invention relates to a condenser mainly utilized in anair-conditioning system for vehicles, which is constituted by providinga liquid tank next to a header pipe and connecting the liquid tank tothe header pipe via a connecting block.

BACKGROUND ART

A condenser is normally connected to a coolant piping by securing aconnecting block to a header pipe of the condenser and bonding an end ofthe coolant piping to the connecting block. For instance, as disclosedin Japanese Unexamined Patent Publication No. H 10-141888, acommunicating hole 12 is formed at a connecting block 8, a hole 4a isformed at a header pipe 4 as well and the header pipe and the connectingblocked are bonded to each other through furnace brazing with thecommunicating hole 12 and the hole 4a aligned with each other.

In addition, if a liquid tank is provided next to either one of theheader pipes, a structure illustrated in FIG. 8, for instance, may beassumed by bonding the liquid tank to the header pipe via a connectingblock. In this example, numerous flat tubes 2 are inserted at a headerpipe 1 over appropriate intervals and a partitioning plate 3 forpartitioning the header pipe 1 is provided at an appropriate position inthe header pipe 1. Holes 4 and 5 are formed on opposite sides of brazingthe partitioning plate 3 at the header pipe 1. It is to be noted thatthe surface of the header pipe 1 is clad with a brazing material.

At a connecting block 6, an intake-side communicating passage 7 and anoutlet-side communicating passage 8 are formed, connecting stages (forhousing O-rings for sealing) 7a and 8a of the communicating passages 7and 8 are formed on the front side, the rear side of the connectingblock 6 is formed as a straight surface, the communicating passages 7and 8 are aligned with the holes 4 and 5 of the header pipe 1 and thebrazing material on the surface of the header pipe melts to weld theconnecting block 6 to the header pipe 1 during the furnace brazingprocess.

However, while the connecting block 6 is welded onto the header pipe 1,the brazing material melting from the surface of the header pipe 1enters the communicating passages 7 and 8 via the brazing surface toreach the connecting stages 7a and 8a which are not brazing surfaces tolower the surface accuracy of the connecting stages 7a and 8a. As aresult, the sealing function achieved through the O-rings is compromisedto cause a coolant leak.

Accordingly, an object of the present invention is to ensure that thesealing function achieved at the connecting stages is not compromised bypreventing the brazing material at the surface of the header pipe fromentering the communicating passages for coolant intake/outlet at theconnecting block during the furnace brazing process.

DISCLOSURE OF THE INVENTION

In the condenser according to the present invention having a liquidtank, which is also provided with a header pipe at least on one sidewith the liquid tank set next to the header pipe, a connecting blockutilized to connect the liquid tank is provided with a pair ofcommunicating passages for coolant intake/outlet, pipe-like projectionsare formed at the communicating passages on the side where theconnecting block is connected to the header pipe and the connectingblock is welded to the header pipe with the pipe-like projectionsinserted at holes formed at the header pipe clad with a brazingmaterial, and the pipe-like projections are located between flat tubesinserted and fixed to the header pipes.

Thus, since the pipe-like projections at the connecting block utilizedto connect the liquid tank are projected between the flat tubes insertedand fixed to the header pipes, the brazing material at the surface ofthe header pipe is not allowed to enter the communicating passages evenwhen it melts, to ensure that the sealing function achieved at theconnecting stages is not compromised, and even if the pipe-likeprojections are inserted into the header pipes and project insidethereof, they can avoid interfering with the flat tubes.

In addition, the pitch of the pipe-like projections at the pair ofcommunicating passages formed at the connecting block is an integralmultiple of the pitch of the flat tubes inserted at and connected to theheader pipe.

Furthermore, the pipe-like projections at the communicating passages ofthe connecting block are loosely inserted at the holes formed at theheader pipe. Alternatively, the pipe-like projections at thecommunicating passages of the communicating block may be fitted insidethe holes formed at the header pipe through press fitting.

As described above, the pipe-like projections are loosely inserted atthe holes formed at the header pipe with a clearance or they are fittedinside the holes formed at the header pipe through press fitting bysetting the diameter of the holes at the header pipe almost equal to theexternal diameter of the pipe-like projections. In the latter case, atemporary retention of the connecting block to the header pipe whichmust be achieved prior to the brazing process is realized.

The distance over which the pipe-like projections at the communicatingpassages of the connecting block project out is set larger than the wallthickness of the header pipe. Since this allows the pipe-likeprojections to project out into the header pipe, the melted brazingmaterial cannot enter the communicating passages.

Note that while the shape of the pipe-like projections at thecommunicating passages of the communicating block normally have acircular section, they may be formed to have a flat section to be usedin conjunction with flat tubes set over smaller intervals (smallerpitch).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of the condenser achieved in an embodiment of thepresent invention;

FIG. 2 presents an enlarged side view of the condenser in FIG. 1 havingthe liquid tank provided next to the header pipe;

FIG. 3 presents an enlarged front view of an essential portion of thecondenser, showing a state in which the connecting block is mounted atthe header pipe;

FIG. 4 presents an enlarged sectional view of the essential portion ofcondenser taken along the longitudinal direction;

FIG. 5 is a sectional view of the connecting block shown in FIG. 3 takenalong line A-A′;

FIG. 6 is a sectional view of the connecting block shown in FIG. 3 takenalong line B-B′;

FIG. 7 is an enlarged sectional view taken along the longitudinaldirection, showing another embodiment of the present invention in astate in which the connecting block is mounted at the header pipe; and

FIG. 8 presents a sectional view of a connecting block in the prior artmounted at the header pipe.

BEST MODE FOR CARRYING OUT THE INVENTION

The following is an explanation of the embodiments of the presentinvention given with reference to the drawings.

In FIG. 1, a condenser 11 utilized in an air-conditioning system forvehicles includes a pair of header pipes 12 and 13, a plurality of flattubes 14 communicating between the pair of header pipes 12 and 13 andcorrugated fins 15 inserted and bonded between the flat tubes 14. Undernormal circumstances, the header pipes 12 and 13 are set to extend alongthe vertical direction as shown in the figure and air flowingperpendicular to the sheet of paper on which the figure is drawn isallowed to pass between the fins 15.

In the header pipes 12 and 13, each achieved by forming an aluminummaterial clad with a brazing material into a cylindrical shape toconstitute a header main body and closing the openings at the two endsof the header main body with lids 16, numerous tube insertion holes 17at which the flat tubes 14 are inserted are formed in alignment alongthe lengthwise direction and in the structural example adopted in theembodiment, an intake connector 19 through which a heat exchangingmedium (coolant) flows in is connected at an upper position, and anoutput pipe 20 through which the heat exchanging medium flows out andits outlet connector 21 are connected at a lower position of one of theheader pipes, i.e., the header pipe 2.

The header pipes 12 and 13, which are formed through cold drawing or bybending a plate material into a cylindrical shape, are partitioned bypartitioning plates 23 a and 23 b and partitioning plates 24 a and 24 brespectively, and with the spaces inside them thus partitioned into aplurality of flow passage chambers 25 a, 25 b and 25 c and flow passagechambers 26 a, 26 b and 26 c respectively, various groups of flat tubes14 are formed to allow the coolant to sequentially flow through theindividual groups of flat tubes 14. In this embodiment, the so-called3-pass flow in which the coolant achieves a serpentine flow from theheader pipe 12 to the header pipe 13, then from the header pipe 13 tothe header pipe 12 and again from the header pipe 12 to the header pipe13 is adopted. The lowermost group of flat tubes 14 defined by thepartitioning plates 23 b and 24 b constitutes a super cooling heatexchanging unit 27 that further cools down the liquefied coolant flowingout from a liquid tank 31 to be explained below.

At the header pipe 13, a bracket 28 for securing the liquid tank 31 isprovided at an upper position and a connecting block 30 for connectingthe liquid tank 31 is mounted at a lower position.

In FIG. 2, which presents an enlarged side view of the condenser 11, theliquid tank 31 that is provided next to one of the header pipes, i.e.,the header pipe 13, is held by the bracket 28 on one side and isinterlocked and retained at screw holes 45 of the connecting block 30via mounting screws 33 on the lower side. It is to be noted thatalthough not shown, inside the liquid tank 31 is allowed to communicatewith the flow passage chambers 26 b and 26 c of the header pipe 13 viaintake/outlet communicating holes 36 and 37 formed at the connectingblock 30.

In FIGS. 3 through 6, the connecting block 30 is a rectangularparallelopiped elongated in the vertical direction, in which twocommunicating holes 36 and 37 are formed. The pitch of the communicatingholes 36 and 37 is an integral multiple of the pitch of the flat tubes14.

Connecting stags 39 an 40 which gradually widen to facilitate connectionto the liquid tank 31 are provided at the front sides (where the liquidtank is connected) of the communicating holes 36 and 37, and on theopposite sides of the communicating holes 36 and 37, i.e., on the sidewhere the header pipe is connected, pipe-like projections 42 and 43enclosing the communicating holes 36 and 37 project out. It goes withoutsaying that O-rings which are sealing members, are mounted at theconnecting stages 39 and 40 and that the pipe-like projections 42 and 43are formed in a circular shape.

The distance over which the pipe-like projections 42 and 43 of thecommunicating holes 36 and 37 project out is set larger than the wallthickness of the header pipe 12, e.g., twice as large or even larger,and the diameter of the pipe-like projections 42 and 43 is set smallerthan the distance between the individual flat tubes 14. As a result,when the pipe-like projections are inserted at the header pipe 13, theyare set between flat tubes 14.

In addition, the middle section of the connecting block 30 projects outon both sides along the lateral direction, and screw holes 45 and 45 areformed in the projecting areas. These screw holes 45 and 45 are usedwhen securing the liquid tank 31 with the mounting screw 33.

The connecting block 30 structured as described above is mounted at theheader pipe 13 through a process during which the connecting block 30 isbrazed together with the condenser 11. The mounting process is achievedby inserting the pipe-like projections 42 and 43 at holes 47 and 48formed on the opposite sides from each other relative to thepartitioning plate 24 b of the header pipe 13, and since the diameter ofthe holes 47 and 48 is set larger than the external diameter of thepipe-like projections 42 and 43, the pipe-like projections 42 and 43 areinserted loosely and held through spot welding so that they are retaineduntil the furnace brazing process. The pipe-like projections 42 and 43are inserted between the flat tubes 14 without posing any interference.

When the connecting block 30, which is temporarily held to the headerpipe 13, undergoes the furnace brazing process together with thecondenser 1, the brazing material present at the surfaces of the flattubes 14 melts to weld the flat tubes 14 to the fins 15, the brazingmaterial at both the tubes 14 and the header pipe 13 melts to weld themtogether and the brazing material at the header pipe 13 melts to weldthe connecting block 30 as well. During this process, the melted brazingmaterial is not allowed to travel into the communicating holes 36 and 37projecting into the header pipe 13, and thus no problem occurs.

Another embodiment of the present invention which is illustrated in FIG.7 differs from the previous embodiment in that the pipe-like projections42 and 43 at the communicating holes 36 and 37 of the connecting block30 are press fitted into the holes 47 and 48 of the header pipe 13. Thisembodiment which can be achieved simply by reducing the diameter ofholes 47 and 48, achieves the temporary retention of the connectingblock 30 prior to the furnace brazing process through press fitting. Forthis reason, the embodiment has an advantage of simplicity over theprevious embodiment. It is to be noted that the same reference numeralsare assigned to other portions to eliminate the necessity for a repeatedexplanation thereof.

Although not shown, the pipe-like projections 42 and 43 at thecommunicating holes 36 and 37 of the connecting block 30 may be formedso as to have a flat section in order to support reduced pitch of theflat tubes and to achieve an increase in the flow rate.

INDUSTRIAL APPLICABILITY

As explained above, according to the present invention in which thepipe-like projections at the communicating holes of the connecting blockutilized for liquid tank connection are inserted at the holes formed atthe header pipe to project into the holes, the melting brazing materialfrom the header pipe does not enter the communicating holes during thefurnace brazing process and thus, the function of the communicatingholes is fully realized.

In addition, even though the pipe-like projections are allowed toproject into the header pipe, they are inserted without presenting anyinterference to the flat tubes. Furthermore, by inserting the pipe-likeprojections at the holes formed at the header pipe through pressfitting, they can be utilized for temporary retention as well. Moreover,by forming the pipe-like projections so as to have a flat sectioninstead of forming them in a circular shape, the pitch of the flat tubescan be reduced and the flow rate can be increased without posingproblems.

What is claimed is:
 1. In a condenser which is constituted by at least apair of header pipes, a plurality of flat tubes communicating betweensaid pair of header pipes, fins located between said flat tubes andpartition plates partitioning an inside of each header pipe to form aplurality of flow passage chambers to constitute a plurality of flattube groups, and having a main heat exchanging unit comprising said flattube groups communicating in series, via said plurality of flow passagechambers, with said flow passage chamber in which a connector for anintake to an upstream end, and a super cooling heat exchanging unitconstituted by a last flat tube group and said flow passage chamberslocated at both sides of said last flat tube group and independent fromsaid main heat exchanging unit, in which a liquid tank is providedbetween said main heat exchanging unit and said super cooling heatexchanging unit, said condenser characterized in that: a connectingblock has a pair of communicating holes communicating with an intake andan outlet of said liquid tank, respectively; one of said communicatingholes communicating with said intake of said liquid tank is communicatedwith the flow passage chambers through a pipe-like projection extendingat a specific length into the flow passage chamber positioned at adownstream end of said main heat exchanging unit; another of saidcommunicating holes communicating with said outlet of said liquid tankis communicated with the flow passage chambers through a pipe-likeprojection extending at a specific length into the flow passage chamberpositioned at an upstream end of said super cooling heat exchangingunit; and each of said pipe-like projections extends between said flattubes inserted and fixed in said header pipe.
 2. A condenser accordingto claim 1, characterized in that: the pitch of said pipe-likeprojections at said pair of communicating passages formed at saidconnecting block is an integral multiple of the pitch of flat tubesinserted at and connected to said header pipe.
 3. A condenser accordingto claim 2, characterized in that: said pipe-like projections at saidcommunicating passages of said connecting block are formed so as to havea circular section.
 4. A condenser according to claim 2, characterizedin that: said pipe-like projections at said communicating passages ofsaid connecting block are formed so as to have a flat section.
 5. Acondenser according to claim 2, characterized in that: a side surface ofsaid connecting block on which said pipe-like projections are formed isformed concavely along said header pipe.
 6. A condenser according toclaim 1, characterized in that: said pipe-like projections at saidcommunicating passages of said connecting block are loosely inserted atsaid holes formed at said header pipe.
 7. A condenser according to claim6, characterized in that: said pipe-like projections at saidcommunicating passages of said connecting block are formed so as to havea circular section.
 8. A condenser according to claim 6, characterizedin that: said pipe-like projections at said communicating passages ofsaid connecting block are formed so as to have a flat section.
 9. Acondenser according to claim 6, characterized in that: a side surface ofsaid connecting block on which said pipe-like projections are formed isformed concavely along said header pipe.
 10. A condenser according toclaim 1, characterized in that: said pipe-like projections at saidcommunicating passages of said connecting block are fitted in said holesformed at said header pipe through press fitting.
 11. A condenseraccording to claim 10, characterized in that: said pipe-like projectionsat said communicating passages of said connecting block are formed so asto have a circular section.
 12. A condenser according to claim 10,characterized in that: said pipe-like projections at said communicatingpassages of said connecting block are formed so as to have a flatsection.
 13. A condenser according to claim 10, characterized in that: aside surface of said connecting block on which said pipe-likeprojections are formed is formed concavely along said header pipe.
 14. Acondenser according to claim 1, characterized in that: the distance overwhich said pipe-like projections at said communicating passages of saidconnecting block project out is set larger than the wall thickness ofsaid header pipe.
 15. A condenser according to claim 14, characterizedin that: said pipe-like projections at said communicating passages ofsaid connecting block are formed so as to have a circular section.
 16. Acondenser according to claim 14, characterized in that: said pipe-likeprojections at said communicating passages of said connecting block areformed so as to have a flat section.
 17. A condenser according to claim14, characterized in that: a side surface of said connecting block onwhich said pipe-like projections are formed is formed concavely alongsaid header pipe.
 18. A condenser according to claim 1, characterized inthat: said pipe-like projections at said communicating passages of saidconnecting block are formed so as to have a circular section.
 19. Acondenser according to claim 1, characterized in that: said pipe-likeprojections at said communicating passages of said connecting block areformed so as to have a flat section.
 20. A condenser according to claim1, characterized in that: a side surface of said connecting block onwhich said pipe-like projections are formed is formed concavely alongsaid header pipe.